CRA\TISHES. 385 



always furnished near the tip with a niedian longitudinal carina. This carina is 

 usually well defined and extends from near tlie acumen l:)ackward to about the 

 middle of the broad flat surface of the rostrum; it is generally followed by an ill- 

 defined and very shallow fo\eola. In less typical specimens the carina is reduced 

 to a very low, rounded, almost invisible elevation just between the lateral angles 

 of the rostrum, or in some cases is wanting altogether; in such specimens the 

 other characters, — cylindrical carapace and broad, flat rostrum, — will hardly 

 be sufficient to separate them from other closely related subspecies. 



"Type, U. S. Nat. Mus. No. 23,962. Gandy Creek, Osceola, Randolph 

 Co., W. Va. W. P. Hay coll., July 12, 1899. Mas, forma secunda. 



"This crayfish is abundant in the main stream as well as in the tributaries 

 of the Tygart's Valley and Cheat Rivers in Randoliih County, West Virginia. 

 I have collected typical examples from the Tygart's Valley River at Beverly 

 and near Elkins. It is most abundant, however, further east in the Cheat River 

 basin, and Osceola may be regarded as approximately the centre of its distribu- 

 tion."— W. P. Hay M8. 



C. h. carinirostris Hay is a slightly differentiated local form of C. bartonii 

 found chiefly in the mountain streams of Randolph Co., W. Va., the Cheat and 

 Tygart's Valley Rivers and their tributaries. Outside of Randolph County, Mr. 

 Hay secured a few specimens at Albright, Preston Co., at Queens, Upshur Co., 

 in the above-named river-basins. It is also probably to be found in the upper 

 waters of the Kanawha River basin further to the south, since there are a few 

 specimens in the U. S. National Museum (Nos. 23,975, 28,605) from the West 

 Fork of the Greenbrier River, near Durbin, Pocahontas Co., and from Laurel 

 Creek, in second Water Cave, near Greenville, Monroe Co., that are pretty char- 

 acteristic examples of this race. 



The median carina on the upper surface of the rostrum is a rather elusive 

 character, in many individuals it is scarcely if at all apparent. Such specimens 

 retain, nevertheless the peculiar quadrangular outline of the rostrum, which 

 is often a trifle broader at the base of the acumen than it is in the middle. 

 The areola is of moderate width and not so thickly pitted as it is in C. b. 

 montanus. 



The dimensions of Mr. Hay's type are as follows: — 



Length, 63 mm.; length of carapace, 32 mm.; length of areola, llj mm.; 

 width of areola, 21 nun. ; width of rostrum Ijetween the eyes, 4 mm. ; length of 

 chela, 25 mm.; breadth of chela lli mm.; length of dactylus, I62 mm. 



